Hot weather and climate change – a mountain from a molehill?


Guest essay by Steve Goreham

Originally published in The Washington Times

On Sunday, Death Valley temperatures reached 129oF, a new June record high for the United States, according to the National Weather Service. Temperatures at McCarran International Airport in Las Vegas reached 117oF, tying the previous record set in 1942 and 2005. National Geographic, NBC News, and other media ran stories attributing the Southwest heat wave to human-caused global warming. But history shows that today’s temperatures are nothing extraordinary.

The United States high temperature record was set in 1913, measured in Death Valley on July 10th. Twenty-three of the 50 US state high temperature records date back to the decade of the 1930s. Seventy percent of state high records were set prior to 1970.

The alarm about climate change is all about one degree. According to the National Oceanic and Atmospheric Administration (NOAA), global surface temperatures have increased about 1.3oF (0.7oC) since 1880. Proponents of the theory of man-made warming claim that this is evidence that man-made greenhouse gases are raising global temperatures.

One degree over more than 130 years isn’t very much. In contrast, Chicago temperatures vary from about -5oF to 95oF, about 100 degrees, each year.

When compared to this 100-degree annual swing, the rise in global temperatures since the 1800s is trivial, captured by a thin line on a graph.


Nevertheless, NOAA repeatedly raises concern about global temperatures. The NOAA website proclaims that “May 2013 global temperatures were the third highest on record.” This sounds alarming unless one understands that “on record” refers to the thermometer record, which only dates back to about 1880.

Climate changes over hundreds and thousands of years. Data from ice cores show several periods during the last 10,000 years that were warmer than today, including the Roman Climate Optimum at the height of the Roman Empire and the Medieval Warm Period, when the Vikings settled southwest Greenland. The warm and cool eras since the last ice age were due to natural climate cycles, not greenhouse gas emissions. The “on record” period that NOAA references is only a tiny part of the climatic picture.


Global average temperature is difficult to measure. The data sets of NOAA are an artificial estimate at best. They start with a patchwork collection of thousands of thermometer stations that inadequately cover the globe. Station coverage of the oceans and of the far northern and southern regions is inconsistent and poor. To cover areas without thermometers, averaging estimates are made from surrounding stations to try to fill in the holes.

In addition to coverage problems, gauge measurements often contain large errors. Man-made structures such as buildings and parking lots absorb sunlight, artificially increasing local temperatures. Cars, air conditioners, and other equipment generate heat when operating, creating what is called an Urban Heat Island effect.

The accuracy of the US temperature record is questionable. Meteorologist Anthony Watts, creator of the science website WattsUpWithThat, led a team of volunteers that audited more than 1,000 US temperature gauge stations from 2007 to 2011. Over 70 percent of the sites were found to be located near artificial heating surfaces such as buildings or parking lots, rated as poor or very poor by the site rating system of the National Climatic Data Center, a NOAA organization. These stations were subject to temperature errors as large as 3.6oF (2oC).

Simple problems can throw off gauge readings. Temperature stations are louvered enclosures that are painted white to reflect sunlight and minimize solar heating. As the station weathers and the paint ages, gauge stations read artificially high temperatures. A study published last month found that after only five years of aging, temperature stations will record a temperature error of 2.9oF (1.6oC) too high. This is greater than the one degree rise in the last 130 years that NOAA is alarmed about.

In addition to temperature measurement error, NOAA makes “adjustments” to the raw temperature data. According to a 2008 paper, after raw thermometer data is received, a computer algorithm “homogenizes” the data, adjusting for time-of-observation, station moves, thermometer types, and other factors to arrive at the official temperature data set.


This sounds good until one looks at the adjustment that NOAA has added. For temperature data from 1900 to 1960, very little adjustment is added. But after 1960, NOAA adds an upward adjustment to the thermometer data that rises to 0.5oF (0.3oC) by the year 2000. This gives a whole new meaning to the phrase “man-made global warming.”

Heat waves are real just as climate change is real. But a heat record in Las Vegas or one degree of temperature rise since the Civil War is not evidence that humans should be overly alarmed when other factors have been shown to be contributors of the same or greater magnitude than the posited temperature rise from greenhouse gas emissions.

Steve Goreham is Executive Director of the Climate Science Coalition of America and author of the new book The Mad, Mad, Mad World of Climatism: Mankind and Climate Change Mania.


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well…you do have to adjust up for UHI and fading white wash

Chris @NJSnowFan

Anyone have exact dates when pavement instead of concert was started to be used in cities. Seems my records show that heat absorbing pavement and roofing material cane into use just about the time temperature gauges starting showing increases in city temperatures.

Brian H

Given a ‘secular’ trend of about 1°C natural rebound since the LIA, there is precious little, or F-all, rise left to be explained by CO2. In fact, the increase in CO2 itself is following the demonstrated 800 yr lag of warming oceans from about 1300 AD, height of the MWP.
It’s natural variability all the way down, folks.

James Ard

I don’t mean to bother the mods going into the holiday. But I’m going to have to start calling them Stable Climate Dworders.

Chris @NJSnowFan said:
July 3, 2013 at 2:31 pm
“Anyone have exact dates when pavement instead of concert was started to be used in cities.”
03 December 1979: The Who concert where people were trodden upon as though they were pavement.

Brian H

RU joking? Those are systemic measurement errors that must be compensated for by adjusting readings DOWN! You’ve got the sign wrong!!


Hi Chris
Good point.
I assume you meant ‘concrete’?


I think the EPA and DOE just gave Latitude a grant based on that statement.


The alarm about climate change is all about one degree. According to the National Oceanic and Atmospheric Administration (NOAA), global surface temperatures have increased about 1.3oF (0.7oC) since 1880.

And how much of that increase took place between 1880 to 1940? I maybe wrong here but I vaguely recall that man-made co2 started having a discernible effect after 1950??? Not sure, can’t recall clearly. Ahhhh, here it is, quoted from the chaps at CRU.

This work played a critical role in the conclusion reached by the 1995 assessment of the IPCC that “the balance of evidence suggests that there has been a discernible human influence on global climate”. Subsequent IPCC reports have strengthened these statements (in 2001: “there is new and stronger evidence that most of the warming observed over the last 50 years is attributable to human activities” and in 2007: “most of the observed increase in globally averaged temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations”) and led most governments, industries, multi-national companies and the majority of the public to accept that the climate is warming, and humans are part of the cause.

So, what I want to know is how much of the warming since 1880 is was actually caused by man? That 0.7C needs to be sliced into 2 pieces.
[1850 to ‘present’ global mean temperature]

jai mitchell

while the temperatures at greenland (and north america!) have gone up considerably since the depths of the last ice age, the global average temperature is generally accepted to have only risen between 4-6 degrees Centigrade. Which is why 2 degrees C is considered to be the amount of averaged global temperature rise that will incur catastrophic damage.


Oh, and I should mention UHI, ‘necessary adjustment’s, airport air-conditioning vents, flaking paint on screens revealing darker material, increased research funding, delusions of fame, ill deserved Ig-Nobel prizes. You really do have to ask yourself how much of this hot propaganda is real?

jai mitchell says:
“… the global average temperature is generally accepted to have only risen between 4-6 degrees Centigrade. Which is why 2 degrees C is considered to be the amount of averaged global temperature rise that will incur catastrophic damage.”
So, the global temperature has already increased by up to 4ºC — with zero global damage or harm — but if it warms another 2º, there will be “catastrophic damage”.

John R T

Chris @NJSnowFan says: July 3, 2013 at 2:31 pm
Come to Richmond, VA, to ride on cobblestones, especially common in alleys.
Actual history:
“Called at various times asphalt pavement, blacktop, tarmac, macadam, plant mix, asphalt concrete, or bituminous concrete, asphalt pavements have played an important role in changing the landscape and the history of the U.S. since the late 19th century.”

Unite Against Greenfleecing

1913 never happened, it was considered to be an unlucky year so in 1912 an executive EPA order was issued directing the new year to proceed straight to 1914. The climate models have been adjusted to reflect this.

Perhaps that will put things in perspective for you J Mitchell

Theo Goodwin

Scientists who are serious about climate science would insist that existing temperature records must be replaced with new measurement regimes that satisfy all the safeguards that are built into the scientific method. After a few decades for design and implementation and a few decades for gathering data, we might actually know something about temperature change. Anything short of that produces nothing but alarmist propaganda and sceptic debunking of alarmist propaganda.
Would I toss all existing data? Without a doubt. None of it is sufficiently accurate or reliable to support the claims of climate science. To paraphrase Socrates, recognizing one’s ignorance is the beginning of knowledge.


This just in from the BBC…
Climate extremes are ‘unprecedented’
“The Earth experienced unprecedented recorded climate extremes during the decade 2001-2010, according to the World Meteorological Organisation…”
“experienced unprecedented recorded”. That’s an odd turn of phrase.


Anthony writes “In addition to temperature measurement error, NOAA makes “adjustments” to the raw temperature data.”
I’d love to know whether those TOBS adjustments are made from the reading meta data (ie times associated with the reading really did change) or whether they’re from assumed reading time changes due to policy changes.
IMO there will always be legitimate reasons why some measurements are taken at different times even by the best meaning people and I’ve no doubt plenty of people read early in the morning before any policy change and similarly plenty of people read in the evening after the policy change.
So what I’d persdonally like to see is the data underlying those adjustments.


re: My previous comment, I see that Anthony didn’t write it, it was a guest poster, Steve Goreham. Sorry to put words in your mouth Anthony 😉

Chuck Nolan

jai mitchell says:
July 3, 2013 at 2:47 pm
while the temperatures at greenland (and north america!) have gone up considerably since the depths of the last ice age, the global average temperature is generally accepted to have only risen between 4-6 degrees Centigrade. Which is why 2 degrees C is considered to be the amount of averaged global temperature rise that will incur catastrophic damage.
What are you afraid of?
What harm do you expect to come to you?
What makes you think 2°C increase in temp will be bad?


Which is why 2 degrees C is considered to be the amount of averaged global temperature rise that will incur catastrophic damage.
Well Jai, could you supply some evidence for that claim? You see, it is quoted often by the IPCC and others as some sort of agreed upon limit, but I’ve never seen a study justifying that number. It is a number that gets thrown around a lot, but where’s the actual studies that show that it is true? Can you point to any?
In fact, do you even know how the 2 degrees is actually measured? I’ll let you in on a little secret. What you THINK 2 degrees means and what the IPCC actually means are two different things. The IPCC estimates that direct effects of CO2 doubling result in about +3.7 w/m2 which in turn results in about +1 degree. But where does this 1 degree happen?
Temperature and w/m2 vary according to the equation:
With P in w/m2 and T in degrees K. So, average temperature of earth is 15 C or 288 K. Plug 288K into the formula and you will get 390.1 w/m2. Add 3.7 w/m2 and you will get a temperature increase of 0.68 degrees. So where does 1 degree come from?
I know the answer, but I’d like to see if you can figure it out on your own. Perhaps you’ll learn something in the process, though I doubt you’ll even try.


don’t ask me how this got on ABC Australia, tho it is ABC Rural!
3 July: ABC Rural: Rising carbon dioxide is greening deserts
Rising levels of carbon dioxide have increased vegetation growth in the world’s deserts by as much as 11 per cent over the last 30 years.
CSIRO, in collaboration with the Australian National University, used satellite records from arid areas of Australia, North America, Africa and the Middle East to assess changes in foliage growth.
Dr Randall Donohue says carbon dioxide increases the water efficiency of arid-zone plants.
“From 1982 to 2010, carbon dioxide levels have increase 14 per cent,” he said.
“It’s been understood for a while that plants do a lot better under elevated carbon dioxide levels.
“Carbon dioxide is an essential ingredient for plant growth, the more they have, generally the better they do.
“That means plants in dry places can end up being more water efficient, and can grow a little bit more for a given bit of rainfall…
“It will also have implications for carbon farming and carbon accounting, but a lot more research is needed to understand what these implications are.”


fixing the market:
3 July: Deutsche Welle: European Parliament votes to revamp emissions trading
Delegates in Strasbourg voted by 344 to 311 to back the delay, with carbon allowance prices having dropped to below 5 euros ($6.5).
The system, introduced in 2005, was designed so that power companies and large industrial concerns could trade carbon permits…
The decision was also praised by the World Wide Fund for Nature (WWF), who nevertheless added that more could be done. “The European Parliament has done the minimum to rescue the Emissions Trading System from redundancy,” Sam van den Plas, climate change policy officer for the World Wildlife Fund, said. “Member states should back further measures to eliminate these toxic tonnes permanently from the EU’s carbon market.”
However the Federation of German Industry (BDI) said that parliament’s decision “sent the wrong signal.”
“Instead of strengthening the European growth motor of industry, the approach of the EU is unsettling and irritating industry across Europe,” the BDI said.


3 July: Bloomberg: Alex Morales: UN Charts ‘Unprecedented’ Global Warming Since 2000
The planet has warmed faster since the turn of the century than ever recorded, almost doubling the pace of sea-level increase and causing a 20-fold jump in heat-related deaths, the United Nations said.
The decade through 2010 was the warmest for both hemispheres and for land and sea, the UN’s World Meteorological Organization said today in an e-mailed report examining climate trends for the beginning of the millennium. Almost 94 percent of countries logged their warmest 10 years on record, it said.
“The decadal rate of increase between 1991-2000 and 2001-2010 was unprecedented,” WMO Secretary-General Michel Jarraud said in a statement. “Rising concentrations of heat-trapping greenhouse gases are changing our climate, with far-reaching implications for our environment and our oceans.” …
Deaths from heatwaves surged to 136,000 in the 10-year period from fewer than 6,000 the previous decade, mainly a result of extreme temperatures in Europe in 2003 and in Russia in 2010, according to the WMO. A total of 511 disasters related to tropical cyclones killed 170,000 people and caused $380 billion of economic damage. Deaths from storms and floods fell…
The average global temperature for 2001-2010 was 14.47 degrees Celsius, according to the report. That’s 0.21 degree warmer than 1991-2000 and 0.79 degree warmer than 1881-1890. …
Sea levels rose at 3 millimeters (0.12 inch) a year, almost double the 20th-century rate of 1.6 millimeters a year…
4 July: Bloomberg Slideshow: Tom Randall: Leaked! Proceedings of the Flat Earth Society
Click ahead to view items from the Flat Earth 2013 agenda, areas where public opinion and behavior pay little deference to the findings of pesky evidence-based science.
Note: this slideshow has no intentional relationship to organizations of real humans that may refer to themselves as the Flat Earth Society.


What caused the previous record temperature in Death Valley???

jai mitchell

If the difference from four degrees average means ice a mile thick over new york to now, then, yes, another 2C average warming from today is a very big deal!
At 2 degrees I expect that the arctic will begin to experience spring ice flow cover loss and an ice free condition around mid June. This will produce an additional average arctic warming of 4-6C, and possibly a peak of 8C higher than normal. This will cause a catastrophic melt of permafrost and the release of stored carbon.
at the same time, the weakening of the jet stream will cause significant changes in the weather patterns, leading to prolonged droughts in the west and southwest and monsoonal floods and atmospheric rivers similar to the Great tennessee flood of 2010.
The most significant effect will be in the loss of Lake powell and the colorado river in the west, the loss of maize and soybean crops and the increase in global food prices. in addition, by 2070 sea level rise will reduce the rice production in low-level valleys in south east asia, leading to extreme food shortages.

John Tillman

jai mitchell says:
July 3, 2013 at 2:47 pm
while the temperatures at greenland (and north america!) have gone up considerably since the depths of the last ice age, the global average temperature is generally accepted to have only risen between 4-6 degrees Centigrade. Which is why 2 degrees C is considered to be the amount of averaged global temperature rise that will incur catastrophic damage.
The Holocene has already been globally two degrees C warmer than now without any harmful effects, indeed humanity flourished. For centuries if not millennia during the Holocene Climatic Optimum, the world was at least that much warmer than now, much more so at high latitudes (up to nine degrees C in winter) & perhaps only one degree C warmer in the tropics.
This was still not as warm as during the prior Eemian interglacial, but still nice & comfy.
So during the past 11,400 years, it has been two degrees or more colder than now & two degrees warmer. IMO the estimate of only four degrees C warmer globally now than at the Last Glacial Maximum 18-20 kya is too low, but the higher guess of six degrees for the HCO might be about right.
Setting aside issues of how a global temperature might be measured when it’s two dozen degrees or more colder over northern North America, Europe & Asia under vast ice sheets.


jai mitchell says:
July 3, 2013 at 2:47 pm
while the temperatures at greenland (and north america!) have gone up considerably since the depths of the last ice age, the global average temperature is generally accepted to have only risen between 4-6 degrees Centigrade. Which is why 2 degrees C is considered to be the amount of averaged global temperature rise that will incur catastrophic damage.

Please provide two pieces of peer reviewed evidence for the

“2 degrees C is considered to be the amount of averaged global temperature rise that will incur catastrophic damage”

PS, some people say that this 2C figure was pulled right out of someone’s arse. What do you say?

…..—–Original Message—–
From: Phil Jones []
Sent: Thursday, September 06, 2007 6:40 PM
Subject: Re: EPP Document on Climate Change…….
“The 2 deg C limit is talked about by a lot within Europe. It is never defined though what it means. Is it 2 deg C for the globe or for Europe? Also when is/was the base against which the 2 deg C is calculated from? I know you don’t know the answer, but I don’t either! I think it is plucked out of thin air. I think it is too high as well. If it is 2 deg C globally, this could be more in Europe – especially the northern part. A better limit might be maintaining some summer Arctic sea ice!…..”

Chad Wozniak

The blind leading the deaf leading the insensible
The impertinent leading the arrogant leading the egomaniacal
I never cease to be amazed at the effrontery of the people who persist in demitting this sort of flatulence. White is not black, red is not blue no matter how many times they say it is.


jai mitchell says: blah, blah, blah.
Please back up your scientific claims from the mountains of peer reviewed evidence. Don’t be shy now.

John Tillman

Chuck Nolan says:
July 3, 2013 at 3:44 pm
“Catastrophe” might look like the Eemian, when Scandinavia was an island. But even then, the Greenland & West Antarctic ice sheets only melted a little around the edges & the East Antarctic ice sheet scarcely changed at all. London might swing even more with some hippos in the Thames.
However, the Holocene is in its waning centuries or millennia & nothing humans can do will raise global temperatures to Eemian levels.

jai mitchell

not sure where you get your equation, but it is wrong.
“If Earth were a blackbody without climate feedbacks the equilibrium response to 4 W/m2 forcing would be about 1.2°C (Hansen et al., 1981, 1984; Lacis et al., 2010), implying that the net effect of all fast feedbacks is to amplify the equilibrium climate response by a factor 2.5. GISS climate models suggest that water vapor and sea ice feedbacks together amplify the sensitivity from 1.2°C to 2-2.5°C. The further amplification to 3°C is the net effect of all other processes, with the most important ones probably being aerosols, clouds, and their interactions. ”
oh, check this out!


Slightly OT, but has anyone heard that Waco, TX had a RECORD low this week???


I thought jai got banned from WUWT for several lifetimes….

Lance Wallace

Re the 2-degree C discussion: In his recent textbook on economics, Richard Tol (an IPCC economist) reviews 14 studies attempting to calculate economic impacts from global temperature increase.
The overall message from those studies is that there will be a net global benefit for temperature increase up to 2 C, becoming a net cost only for temperatures > 2 C.


Thanks, Lance Wallace.
OK, so if CS be one K for the first doubling in CO2 from ~400 to ~800 ppmv & less than one K for the second doubling to ~1600 ppmv, then I’d say that humans will never get to enjoy that two degree C bounty.


We are the experiment, yet can’t quite get a grip on the changing conditions.
They must be changing ?
How much ?
Which leaves the big question, why?
Consensus leaves a lotta room for error, and scientists.
Don’t know if it pays, but the data has never been more abundant.
Time to put it to “good” use. Instead of chasing a phantom, that admittedly will need to be put to rest, first.

Sam the First

Meanwhile yesterday in Canada’s North West Territories (Iqaluit) – a fortnight after midsummer!


Sam – gotta love the NWT – can’t rely on summer showing up in summer!
Meanwhile, in Calgary yesterday we reached 35C, as recorded in several parts of the city including my 3 thermometers. The airport only got to 32C, which demonstrates that they are in a different climate zone (official records for the city only come from someplace just outside the city – typical for government work I guess).
Today we barely made 21C, with clouds and a cool breeze. Typical.
Unfortunately, I managed to get what is possibly the worst sunburn I’ve ever had. My 8-year old insisted on swimming all afternoon and into the evening, and although she’s a bit burned I’m the one who is supposed to know better. It’s rare we get days that warm!
You’d think the warm day would be welcomed by those cleaning up the floods, but no. I’ve already got a few facebook links to how this is all “climate change”. Sigh.

Owen in GA

jai mitchell says:
July 3, 2013 at 4:36 pm
not sure where you get your equation, but it is wrong.

There are a whole bunch of physicists waiting to award you the Nobel Prize In Physics if you can provide to the world the scientific proof that the Stefan–Boltzmann law is invalid, because David M Hoffer quoted it exactly. It has been seen to work many times, but as Einstein said it only takes one experimental fact to prove it wrong.

Owen in GA

Owen in GA says:
Your comment is awaiting moderation.
July 3, 2013 at 5:19 pm

I wonder what I said to be placed in the penalty box?

Rob Dawg

Las Vegas. Near 2 million more 100°F people exhaling CO2 and H2O and driving a million 400° autos running air condition and evaporating billions of gallons of water from myriad sources while converting the landscape from flat and light to rough and dark and only a degree difference? Human contribution has got to be zero/noise based on the evidence.


Here in the UK it looks like were are in for the best spell of hot sunny weather for July since July of 2006 come the weekend. Thanks to the jet stream pushing way to the north and so letting a blocking high to settle right over the UK. lts looking like its going to be hang around for at least a week. So after such a poor run run of summers we have had, it will be most welcome.


2 more degrees? One word; Otzi. We’ve been there and done that and no one got hurt… well, ‘ceptin’ Otzi, and that had more to do with a whack to the skull than CO2. You may now proceed to unbunch your panties.
Move along please. Nothing to see this century.

Jai said blah, blah, blah
This morning when I got up it was 6 degrees C. Now it is 20 degrees C. Hate to tell you but I see no ill effects from a 14 degree rise.
Your 2 degrees is nonsense.


not sure where you get your equation, but it is wrong.
As Owen in GA has already pointed out, the equation is correct:
You demonstrate once again that you can quote what other people say, but you don’t actually understand the science behind the quote. I suggest you learn to use the equation, then plug 4 w/m2 into it instead of 3.7 w/m2 at 15 C and see what you get. Then I suggest you read the literature so you can discover for yourself that Hansen’s calculation of 4 w/m2 is slightly high and that the accepted value of the IPCC and the climate science community is, and has been for a long time, 3.7 w/m2 per doubling of CO2, not 4. I suggest also that you read what I said again and this time note that I was talking about the DIRECT effects of CO2 doubling. That said, if you want to include feedbacks, beyond the fact that the IPCC has repeatedly downgraded the consensus estimate of feedbacks, and looks set to do so again in AR5 to the lowest value in some decades, the point I was making still stands. Whatever value you wish to quote, Stefan-Boltzmann Law requires that the average temperature change be about 2/3 on average at earth surface of the number quoted by the IPCC because that number is calculated at the effective black body temperature of earth which is 33 degrees cooler than the average earth surface temperature.
When you are done digesting all that, I suggest you read IPCC AR4 WG1 where they say plain and simple that their calculations for radiative forcing can NOT, repeat NOT be used to extrapolate surface temperatures in the first place. So your 2 degree limit is not only an arbitrary claim, but even the IPCC admits that their calculations don’t provide for measurable numbers on the ground. If you’re going to argue the science, do the rest of us the courtesy of finding out what the published science you purport to represent actually says:

Janice Moore

Topol: “If I were a rich man, daidle deedle deedle deedle daidle deedle deedle DUM!….”
Okay, Jai, you take it from here…
Jai: [singing happily] “If ….. [clear throat] … the difference from four degrees average means ice a mile thick over new york to now [Jersey?]… .”
“If Earth were a blackbodeeeeeeeee… .”
There. “Keep your eyes on the Arctic people.” [from another thread another day]
LOL. DON’T BAN JAI — he is way too much fun.
Here he is! (explains why he didn’t recognize the Boltzmann equation):


Jai-you have been OWNED by davidmhoffer. Suggest you finish freshman year before you try to take on someone with an IQ that, on the available evidence, is at least double that of yours.

Chris @NJSnowFan

Thanks John R T for the link on asphalt.
Yea I did mean to say concrete and not concert. Mobile phone typo..
I see in 1934 there was s boom I asphalt.
But in last 30 years was the real boom from concrete runways to asphalt.


More for J Mitchell
According to the United Nations IPCC AR4 WG1 report, the Level of Scientific Understanding in 11 of 16 categories affecting radiative forcing is either “Low” or “Very Low”. See for yourself:
So J, perhaps after you read the wikipedia article showing I got the SB Law equation bang on, you might want to consult some physics texts or perhaps even some physicists to see if I applied it correctly. After you discover the awful truth, which is that you’re lucky you didn’t place a wager on the matter, you can puzzle out for me how the measured temperature changes of the last century can be attributed to CO2 with any certainty when the effects, positive or negative, of 11 of 16 factors are listed by the IPCC themselves, the very representatives of the consensus science you claim to understand and represent, are not understood?
While you are puzzling over how they can be so certain when they admit uncertainty in the majority of the factors,, you could perhaps consider this quote:
“One must say clearly that we redistribute de facto the world’s wealth by climate policy. One has to free oneself from the illusion that international climate policy is environmental policy. This has almost nothing to do with environmental policy anymore.”
~ Ottmar Edenhofer, Co-Chair, UN/IPCC WG-3

Of course J, we get it. You’re some sort of consultant on climate change. We understand how hard it is to admit you don’t understand the science, or that you might be wrong about the science, when you are one of the people the wealth is being redistributed to.